1. Field of the Invention
The invention relates to a diffuser for an aeration system, and more particularly to a diffuser which allows gas introduced in the aeration system to form small and fine bubbles, so as to increase the concentration of a gas, such as oxygen, that is dissolved in a water pool equipped with the aeration system.
2. Description of the Related Art
In order to establish an aerobic condition commonly used in the treatment of wastewater or sewage, or in the cultivation of biological materials in water pools, an aeration system is employed to increase the oxygen concentration in water.
An aeration system includes a plurality of diffusers adapted to be provided on the bottom of a water pool, conduits connected to the plurality of diffusers, and a blower forcing air to flow into the conduits and to pass through the slits provided in the diffusers, so as form a plurality of bubbles in the water pool.
As shown in FIG. 1, U.S. Pat. No. 5,330,688 discloses a diffuser, which comprises a disk-shaped base 92 connected to a conduit 91 and a disk-shaped membrane diffuser 93 provided on the base 92. With reference to FIG. 2, the disk-shaped membrane diffuser 93, which is made of an elastomeric material, is provided with a plurality of slits 94, which are spaced apart from each other and arranged circularly, to allow the passage of air introduced from the conduit 91 through the slits of the membrane diffuser 93 to form bubbles in the water of a water pool. In order to increase the concentration of the dissolved gas in the water, the slits 94 of the membrane diffuser 93 are as small as possible and are provided at a density that is as high as possible. However, since the elastomeric material is tough and since the membrane diffuser 93 must possess a tensile strength that is sufficient to resist the pressure within a chamber defined by the base 92 and the diffuser membrane 93 when gas is introduced into the chamber, limits are encountered with respect to how small the slits 94 can be made and to how high a density the slits 94 of the elastomeric membrane diffuser 93 can be provided.
The commercially available membrane diffuser for aeration systems is generally made from an elastomeric material of a synthetic rubber, such as ethylene-propylene-diene monomer rubber (EPDM) rubber and a thermoplastic elastomer (TPE), the slits of which are generally millimeter-sized.